﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _1._1_c_sharp
{
    class Program
    {
        static void Main(string[] args)
        {
         Console.Write(" 请输入第一个数字：");
         string A = Console.ReadLine();
         Console.Write(" 请输入运算符(+、-、*、/)：");
         string B = Console.ReadLine();
         Console.Write(" 请输入第二个数字：");
         string C = Console.ReadLine();
         string D = "";
            if (B == "+")
                      D = Convert.ToString(Convert.ToDouble(A) + Convert.ToDouble(C));
            if (B == "-")
                      D = Convert.ToString(Convert.ToDouble(A) - Convert.ToDouble(C));
            if (B == "*")
                      D = Convert.ToString(Convert.ToDouble(A) * Convert.ToDouble(C));
            if (B == "/")
                      D = Convert.ToString(Convert.ToDouble(A) / Convert.ToDouble(C));
             Console.Write(" 输出结果是：" + D);

        }
    }
}
